Stem



Nov. 13, 1934., L. I'(. MARSHALL STEM Filed Oct. '7. 1929 IN VEN TOR v A TTORNE Y.

Patented Nov. 13, 1934 UNITED STATES tests-is STEM Laurence K. Marshall,

Cambridge, Mass, as-

signor to Raytheon Production Corporation, Newton, Mass, a corporation of Delaware Application October 7, 1929, Serial No. 398,052

8 Claims.

This invention relates to stems for vacuum tubes and the like. In the manufacture of vacuum tubes and the like it is customary to dispose the several Wires to be sealed in the glass in a jig and slip a glass tube over them. The tube is then heated to soften the glass and pressed to the desired shape. It is desirable to have a press of such shape as to permit the wires sealed therein to extend upwardly into the tube without 10 bending while supporting the electrode structure. This has the advantage of eliminating the step of bending the wires with the possibly resultant defective seals. Furthermore, heavy spring wire may be used which more effectively supports the electrode structure against shock and vibration. The stem of my invention has a plurality of wings or portions extending in more than one vertical plane, the wings, however, not meeting at a common junction. My preferred form is H- 29 shaped. By having a stem of such a shape, wires may be sealed in various corners to form a rigid skeleton frame work upon which the entire electrode structure of a vacuum tube may be supported.

Referring to the drawing:

Figures 1 and 2 are views of two modifications of stems incorporating :my invention.

The press shown in Figure 1 comprises a tubular stern portion 36 terminating in a flat pinch 30 31. t each end of pinch 31 are wings 32 and 33 substantially at right angles thereto and forming an H. As shown wings 32 and 33 have a plurality of arbors 3 sealed in the corners thereof.

Portion 31 has a number of wires 35 sealed there- 35 in which are adapted to serve as connecting leads to the various electrodes. If desired, any one or more of wires 35 may be made of heavy metal so that one or more electrodes may be supported. an exhaust tube 38 terminates at 39.

A modified form of stem is shown. in Figure 2 wherein pinch 31 shown as substantially thicker than the corresponding portion 31 in Figure 1.

It is evident that supporting arbors may be sealed in any desired portions of either one of the stems shown in Figures 1 and 2.

The presses shown in Figures 1 and 2, while useful with any electrode structure, are especial ly useful for supporting the electrode structures shown in the copending applications of Paul T. Weeks, Serial. No. 396,393, filed September 17, 1928 and Andrew E. Lyle, Serial No. 315,275, filed October 26, 1928, Serial No. 336,243 filed January 30, 1929, Serial No. 381,018, filed July 25, 1929.

It is evident that the press need not have the two end portions at right angles to the intermediate pinch portion to form an H but may be at any desired angle. If desired, one of the end wing portions 32 may be omitted and a T-shaped press be formed instead. For certain electrode structures this'nray be found desirable.

I claim:

1. A stem for a space discharge tube comprising a press having more than two flat wing portions formed directly at the upper end of said stem and disposed in a plurality of planes parallel to the axis thereof, said wing portions being separated so that no more than two Wing portions meet at any one spot.

2. A stem for a space discharge tube comprising a flat press and a single additional flat press at one end at least, of said first mentioned press and angularly disposed to said first-mentioned press.

3. A stem for a space discharge tube comprising a press having a generally H-shaped section in a plane perpendicular to its axis.

4. A stern comprising a press having a generally H-shaped section in a plane perpendicular to its axis, and an upstanding wire standard sealed in each end of each of the two parallel legs of said press.

5. A stem comprising a press having a generally H-shaped section in a plane perpendicular to its axis, an upstanding wire standard sealed in each end of each of the two parallel legs of said press, and a plurality of upstanding wire standards sealed in the transverse leg of said press.

6. A tube stern construction of the character described, comprising a main vertical element supporting portion, a vertical transverse element supporting portion disposed transversely of said main portion at one end thereof, a plurality of main element supporting wires embedded in said main portion and disposed substantially in the same vertical plane, and a plurality of auxiliary element supporting wires embedded in said transverse portion and disposed in a vertical plane transversely of the vertical plane of said main element supporting wires.

'7. A tube stem construction of the character described, comprising a main vertical element supporting portion, a vertical transverse element supporting portion disposed transversely of said main portion at one end thereof, a plurality of verse portion and disposed in a vertical plane 8. A stem for a space discharge tube comprising a fiat press of substantial length, a plurality of additional flat presses disposed. at opposite ends of said first-mentioned press, and angularly disposed to said first-mentioned press.

LAURENCE K. MARSHALL. 

